Watch the NSA's secret surveillance get exposed in the first Snowden trailer

How one man blew the doors off the NSA's operation

The first trailer for Snowden, the film based on the NSA whistleblower, has been revealed.

Starring Joseph Gordon-Levitt and directed by Oliver Stone, the film's trailer shows a dramatic unfolding of the story that shaped the huge privacy and encryption debate which followed.

Snowden is the story of Edward Snowden, the former soldier and CIA employee who blew the doors off the NSA's worldwide digital surveillance operations. As we see in the trailer, it touches on his life before, during and after the revelations.

Edward Snowden even tweeted the trailer, having met with Levitt to help the actor hone his role. It also marks a return of Stone to his conspiratorial ways.